1. Field of the Invention
The invention relates to supplementing the resistance to gas flow in a circuit configured to deliver gas to a subject in order to bring the overall resistance of the circuit to a predetermined level that corresponds to an assumed level of resistance accounted for an a therapeutic algorithm.
2. Description of the Related Art
Systems that deliver pressurized flows of breathable gas to subjects are known. In these systems, a circuit generally carries the gas from a pressure generator to the airway of a subject. These circuits can be configured in accordance with individual preferences of the subject. For example, the interface appliance (e.g., the mask), the circuit length, the physical flexibility of the circuit, and/or other features of the circuit can be configured by the subject. Generally, different circuit configurations will have different resistances to gas flow.
Generally, a system delivers a pressurized flow of breathable gas to a subject in accordance with a predetermined therapeutic algorithm. The algorithm dictates one or more of the parameters of the gas (e.g., pressure, flow rate, composition, temperature, humidity, etc.) delivered to the subject over time. Since some of the parameters of the gas provided to the subject vary within the circuit between the pressure generator and the airway of the subject due to the resistance within the circuit, some conventional systems account for the resistance within the circuit. Typically, this involves controlling the pressure generator to adjust the parameters of the gas as it is emitted by the pressure generator to account for the resistance of the circuit.